JavaScript is the industry standard client-side scripting language
that is used in web applications.Professional JavaScript
Frameworks: Prototype, YUI, Ext JS, Dojo and MooTools offers an
examination of some of the top JavaScript (JS) frameworks that are
available, with practical examples and explanations of what each
does best.

Over the past few years, there’s been a small renaissance
in JavaScript as a language. A variety of projects have sprung up
to build reusable JS libraries and frameworks — and at this
point, a good number of them have matured and shown staying power
that they’re worth taking a serious look at and relying on in
professional projects.

JavaScript has grown in popularity in parallel with the Web and
today is supported by all major browsers and new web technologies.
JavaScript has been extended over time to deliver high-performing
and incredibly impressive Web user experiences, using technologies
including Adobe Flash, AJAX, and Microsoft Silverlight.

As JavaScript is used increasingly for “serious”
development on the Web, the lessons that have been learned and the
tools that have been invented along the way are being consolidated
and shared by developers in the form of libraries and frameworks.
However, since JavaScript is such a flexible and dynamic language,
each framework can present very different approaches to the
problems of web development — each with its own pros and
cons.